Aims: 1) To assess the risk for lung cancer in a cohort of miners with relatively low exposure to radon. 2) To assess the risk for other cancers in uranium miners exposed to radon. 3) To assess mortality associated with underground uranium mining. Accomplishments: We identified 1944 incident cancer cases among miners known to be alive 1977 who were followed using a population-based cancer registry through 1992. Approximately 500 additional cancers were identified between 1992 and 1996. In addition to baseline data on years of underground mining and average annual radiation exposure, detailed exposure histories, including month-to-month changes in radiation exposure, occupational dust exposure, and smoking were obtained for all cancer cases and a year-of-birth stratified random sample of the entire cohort (n=2000) for case-cohort comparisons. An additional cohort of miners employed for less than one year underground was also sampled for case-cohort analysis. Standardized cancer incidence ratios have been estimated for lung cancer and for other cancer sites. Analysis of case-cohort study data has been started. Vital statistics data are also being used to explore non-cancer causes of death among radiation-exposed miners. Manuscripts describing exposure conditions in the mines and reproductive outcomes among offspring of miners have been submitted for publication. Other manuscripts are in preparation.